Storage and processing of a wide range of substances in a dehydrated or frozen form is necessary to retain activity, prevent degradation products from forming and to facilitate handling and transport. Unfortunately, upon rehydration or thawing, many substances tend to aggregate, thereby decreasing their effective concentration and often rendering them useless or forming harmful byproducts.
Various methods have been tried to prevent or eliminate such aggregation. For instance, detergents and chaotropic agents are often used to prevent aggregation of proteins in solution. These agents are thought to prevent aggregation mediated by hydrophobic interactions and thus are limited to prevention of aggregation due to this cause. See, e.g., Tanford and Reynolds (1976) Biochim. Biophys. Acta. 457:133; and Tanford, “The Hydrophobic Effect”, 2nd Ed., Wiley, N.Y. (1980). Such agents may also not be suitable for use where the substances are to be formulated into therapeutic compositions as they may cause adverse reactions. Aluminum salts in solution are in the form of a highly hydrated colloidal gel and carry a surface charge at any pH outside their isoelectric point. Since each colloidal particle carries the same charge, they mutually repel each other and thus naturally form a stable colloidal gel. When the hydration shell is removed (e.g., by freezing or drying) the particles can contact each other and the surface energy causes aggregation.
Trehalose, α-D-glucopyranosyl-α-D-glucopyranoside, is a naturally occurring, non-reducing disaccharide which was initially found to be responsible for protection of intact plant cells from desiccation. Trehalose has been shown to be useful in preventing denaturation of proteins viruses and foodstuffs during desiccation. U.S. Pat. Nos. 4,891,319; 5,149,653; 5,026,566; Blakeley et al. (1990) Lancet 336: 854-855; Roser (1991) Trends in Food Sci. and Tech. pp.166-169; Colaco et al. (1992) Biotechnol. Internat., pp. 345-350; Roser (1991) BioPharm. 4:47-53; and Colaco et al. (1992) Bio/Tech. 10: 1007-1011.
In the field of protein purification it would be particularly useful to eliminate or prevent the tendency of proteins to aggregate upon rehydration and thawing. This is especially important in the area of biopharmaceuticals where the proteins are often used as an ongoing basis of treatment. In the case where protein aggregates form and are injected into a patient, antibodies may form to the protein which diminish the effectiveness of the treatment.
Thus, it would be useful to prevent aggregation of a wide variety of substances particularly those useful in medicine.